Perhaps you should try some spelling variations:
hanh dien » nhanh dien, hang dien, danh dien
cua viet » ca viet, hoa viet, cua vat
dien cua » dieu cua, dien cuc, dien cu
sach ty » sach y, sach thu, xach tay
sach tu » sach thu, cach tu, sach uu
hieu ve » hieu va, hieu van
nang o » nang co, nang ho, nang ro
ve cau » ke cau, va cau, ve cac
luc va » tuc va, loc va
o hoi » co hoi, o hoc, o hai

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sach ty) OR (sach tu)) nang o hoi. hieu ve cau ((luc va) or (duc va)) hanh dien cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach ty) OR (sach tu)) nang o hoi. hieu ve cau ((luc va) OR (duc va)) hanh dien cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach ty) OR (sach tu)) nang o hoi. hieu ve cau ((luc va) or (duc va)) hanh dien cua viet".
• Adding a wildcard symbol may retrieve word variants: te ((sach ty) OR (sach tu)) nang o hoi. hieu ve cau ((luc va) or (duc va)) hanh dien cua viet*.